Welding-controller.



L. P. COULTER. WELDLNG CONTROLLER. APPLICATION FILED lULY 8. I9I51,215,914. mental Feb. 13,1917.

LEONARD P. COULTER, E MILWAUKEE, WISCONSIN, AssIGNoE To THE CUTLEE-HAMMER MEG. oo., or MILWAUKEE, WISCONSIN, A ConroEATioN 0E WIS- coNSIN.

WELDING-CONTROLLER.-

Specification of Letters Patent.

Patented Feb. 1?, 1917 Application filed July 8, 1915. Serial No.38,684.

To MZ whom t may concern Be. it known that I, LEONARD P. COULTER, acitizen of the United States, residing at Milwaukee, in the county ofMilwaukee and .means -for cont-rolling the resistance. It is importantthat the controller automatically return to its initial position whenthe welding circuit is broken so that the circuit will always be insafecondition for operation. The problem has been to devise a controller'which will positively accomplish these and other results with `thefewest number of simple devices. To this end the present invention hasbeen devised.

One of the objectsof the invention is to I provide an improved weldingcontroller which will automatically regulate the Welding current inresponse to the voltage between the yelding electrodes and which willinsure that the welding circuit is always 'in x safe condition foroperation.

Another object is to provide a simplified welding controller which willautomatically exclude a resistance from the welding circuit in` responseto the voltage between the welding electrodes and insure that theresistance is automatically reinserted when the welding circuit isbroken. Q

A further object is to provide an improved controller in'which a singleinstrumentality automatically controls the welding currentin response tothe voltage between the welding electrodes and insures that the weldingcircuit is always in conditon for safe operation.

vOther objects and advantages of the invention will -hereinafter appear.

The accompanying drawing is a diagrammatic view of acontroller embodyingthe A invention.

The controller comprises in general a starting1 resistance 1 and alimiting resistance 2 for regulating the current through 55', theelectrodes 3 and 4, and an automatic ymains through the controller.

Switch 5 for controlling the starting resistance.

The starting resistance is of any suitable type. It is preferablyadjustable as shown sothat the amount of resistance in circuit may bevaried, and it is normally-connected in series with electrodes 3 and 4across supply mains 6 and 7. The starting resistance is lthus initiallyin the welding circuit so that when the resistance between theelectrodes is small, an excessive current will not flow. The resistanceis excluded from the circuit by the automatic switch 5, as will behereinafter described.

The resistance :2,l which is called the limiting resistance, is alwaysin the circuit of the electrodes, and it thereby prevents an absoluteshort-circuit between the supply The resistances of such a value thatsutiicient curren will flow for welding purposes.

The automatic switch 5 has a reciprocat ing plunger Scontrolled b v twowindings 9 and 10, which act lcumulatively thereon. The plunger carriesa contact bridge 11 adapted to engage the stationary contacts 12 and 18.It is normally biased to open position by gravity or by suitable meanssuch as a spring. The 'upper end of the plunger 8V is'connected to anauxiliary switch member 14 by means of a suitable lost motion connectionwhich is adjusted so that the circuit of winding is opened as the switch5 closes. The winding 9 of the switch is connected in series in thewelding circuit as follows: from positive line 6 through electrodes 3and 4, conductor 15, winding 9, contact 12, conductor 1G and resistances1 and 2 to negative line 7. The

4winding 9 is accordingly energized when the welding circuit iscompleted and it exerts a pull on the Iplunger in a direction to closethe switch. The winding is arranged, however, so that its pull on theplunger 8 is insufficient to move the switch to closed position, but issufficient to hold the switch closed after the plunger has been moved byother means.

rPhe winding 10, which may be termeda voltage winding, is connected inshunt to the electrodes 3 and 1. The circuit of this winding is frompositive line 6 through the electrodes 3 and 4, switch 14, winding 10,conductor 17 to positive line 6. When the winding 10 is energized, itexerts 'a pull on the plunger 8 which together'with the pull of winding9 is sufficient to move the switch to closed position.

It should be understood that any other suitable form of switchcontrolled by tWo windings acting cumulatively may be used if desired.,

The controller is shown in normal position with the switch 5 open. Theoperation is as follows: 4 1

When the electrodes 3 and 4 are separated and the resistance of the arcincreases, the voltage drop thereacross correspondingly increases,thereby causing the current through winding 10 to increase. Asthecurrent in winding l0 increases, itsincreasing pull is added to therelatively small pull of winding 9 until a point isreached where thecombined pull of the two windings closes the switch. As the switch 5closes y the upper end of the plunger operates the switch 14 and opensthe circuit of winding 10 but the switch does not return to its normallyopen position since the pull of winding 9 is suiiicient to hold itclosed.

When the switch 5 closes it completes a circuit in shunt to theresistance las follows: from positive line 6` through electrodes 3 and4, conductor 15, winding 9, oontact 12, bridge 11, contact 13, conductor18 and resistance 2 to negative line 7. The winding 9 thus remainsin thewelding circuitandv holds the switch5 closed.

When the welding-circuit is brokenl the winding 9 is denergized and theswitch plunger 8 returns to normal position, there- 'by automaticallyreinserting the resistance l in the welding circuit. The circuit 'of4winding 10 is also automatically closed as the switch 5 returns to itsopen position. The controller thus automatically returns to its normalposition when the welding circuit is broken and reinserts the resistanceto protectthe circuit.

One of the advantages of the controller is that the switch is heldclosed by a Winding which is denergized when the Welding circuit isbroken. This condition would not be present if the voltage winding-wereemployed yto hold the switch closed since if the circuit of this windingwere not opened it would be connected across the line and the switchwould be held closed after being operated, even though the circuit werebroken by the welding electrodes; By the novel construction hereindisclosed a controller is provided which will automatically control thewelding current and at the same time .place lthe controller in normalcondition whenever the welding circuit is broken. The

operation of the switch is delayed until the' resistance of the arc hasincreased. WhenV the resistance ofthe arc has increased to apredetermined value, the switch closes,

whereupon lthe circuit of the operating to reinsert the resistance.

vised which embody the invention and predetermined value,

winding is opened and the switch is held closed by a. winding which isdenergized whenever the welding circuit is broken so that the switchwill return to lopen position Another advantage ,of the controller isthat both the windings act in the saine direction on the movable memberof the switch and accordingly there is no tendency for said member tovibrate or chatter during the operation of the switch.

It should be understood that the controller shown is for purposes ofillustration only, and that other `"structures may be de- 0 which areincluded within the -spirit and 8 scope' of the appended claims.

What I claim as new and'desire to'secure by Letters Patent is: 4

' 1. A welding controller having a'resist-l 85 ance in the circuit of.the electrodes, a switch -j having two windings acting cumulatively toclose the switch to excludev the resistance when the resistance of thearc has reached a said switch being adapted to automatically reinsertthe resistance when the Welding circuit is broken.

2. A welding controller having a starting resistance in the circuit'ofthe electrodes, a switch having two windings actingcumulatively to closetheswitch to exclude the starting resistance when the resistance of thearc has reached a predetermined value, and

`means operated by closure of the switch for opening the circuit of oneof the windings so that the switch will automatically open to reinsertthe resistance when the welding circuit isA broken.

3. A welding controllerv having a starting resistance in the-circuit ofthe electrodes, switch having a winding responsive to the voltagebetween the .electrodes and a windance in the circuit of the electrodes,a

switch having two controlling windings one of which is responsive to thevoltage between the electrodes and the other of which is responsive tothe welding current, and means operated by the closure of the switch foropening the circuit of the voltagewinding so that the switch willautomatically return to open position to reinsert the resistance whenthe welding circuit is broken.

5. A welding controller having a .resistance in the circuit of theelectrodes, a switch alo-5.,

mg. so that-the switch automatically opens 115 Y having two controllingwindings one lof which is responsive to the voltage between thelelectrodes and the other of which is responsive to th`e Weldingcurrent, said switch being adapted upon closure thereof to open thecircuit of the voltage Winding and complete ;1 circuit for the otherwinding and the electrodes in shunt to thestnrting resistance.

6. A welding controller provided with a switch having two windingsacting cumulatively thereon, one of said windings being connected inseries with the Welding electrodes and with a starting resistance in thewelding circuit, the other of said windings' being adapted, when theresistance of the arc has reached a predetermined value, to

close the switch to complete a circuit from position when the weldingcircuit is broken.

In witness whereof, I have hereunto subscribed my name 1n the presence`of two witnesses.

LEONARD P. COULTER. Witnesses:

L. C. SGHANTZ, L. D. MASON.

